public abstract class SingleNodeExpression extends Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, INHERITED_CONTEXT, INSPECTION_CONTEXT, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, NAVIGATION_CONTEXT, NODE_VALUE_CONTEXT, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, W3C_CONSUMING, W3C_FREE_RANGING, W3C_GROUP_CONSUMING, W3C_MOTIONLESS, WATCH_METHOD| Constructor and Description |
|---|
SingleNodeExpression() |
| Modifier and Type | Method and Description |
|---|---|
int |
computeCardinality()
Specify that the expression returns a singleton
|
int |
computeSpecialProperties()
Compute the special properties of this expression.
|
boolean |
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the expression.
|
NodeInfo |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
|
int |
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.
|
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression
|
abstract NodeInfo |
getNode(XPathContext context)
Get the single node to which this expression refers.
|
boolean |
isContextPossiblyUndefined()
Ask whether there is a possibility that the context item will be undefined
|
SequenceIterator |
iterate(XPathContext context)
Evaluate the expression in a given context to return an iterator
|
protected abstract String |
noContextMessage()
Customize the error message on type checking
|
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression.
|
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, copy, doPromotion, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getExpressionCompiler, getExpressionName, getHostLanguage, getImplementationMethod, getIntegerBounds, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getStreamingAdjunct, getSystemId, getSystemId, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSubExpressionInfo, iterateSubExpressions, markTailFunctionCalls, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, toString, typeErrorpublic Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
typeCheck in class Expressionvisitor - an expression visitorcontextItemType - the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPEXPathException - if an error is discovered during this phase
(typically a type error)protected abstract String noContextMessage()
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
optimize in class Expressionvisitor - an expression visitorcontextItemType - the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPEXPathException - if an error is discovered during this phase
(typically a type error)public int computeCardinality()
computeCardinality in class ExpressionStaticProperty.ALLOWS_ZERO_OR_ONE,
StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE,
StaticProperty.ALLOWS_ZERO_OR_MOREpublic ItemType getItemType(TypeHierarchy th)
getItemType in class Expressionth - the type hierarchy cachepublic int getIntrinsicDependencies()
getIntrinsicDependencies in class Expressionpublic int computeSpecialProperties()
ExpressionStaticProperty. The "special" properties are properties
other than cardinality and dependencies, and most of them relate to properties of node sequences, for
example whether the nodes are in document order.computeSpecialProperties in class Expressionpublic abstract NodeInfo getNode(XPathContext context) throws XPathException
XPathExceptionpublic boolean isContextPossiblyUndefined()
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate in class Expressioncontext - the evaluation contextXPathException - if any dynamic error occurs evaluating the
expressionpublic NodeInfo evaluateItem(XPathContext context) throws XPathException
ExpressionevaluateItem in class Expressioncontext - The context in which the expression is to be evaluatedXPathException - if any dynamic error occurs evaluating the
expressionpublic boolean effectiveBooleanValue(XPathContext context) throws XPathException
ExpressioneffectiveBooleanValue in class Expressioncontext - The context in which the expression is to be evaluatedXPathException - if any dynamic error occurs evaluating the
expressionCopyright (c) 2004-2013 Saxonica Limited. All rights reserved.